How Federer can help 'struggling' Kyrgios

Nick Kyrgios has admitted he is struggling mentally and physically after a third injury retirement in as many tournaments put his US Open campaign under a cloud.

Fans booed the 22-year-old Australian off the court after he pulled out of his second-round Washington Open clash on Thursday, his first match of the US hardcourt season.

Kyrgios was down 6-3 3-0 to American world No.106 Tennys Sandgren when he retired with a shoulder problem.

It was Kyrgios' first outing since retiring less than an hour into his Wimbledon first-round match due to a chronic hip injury.

He also pulled out midway through his Queen's Club opening-round clash in June when he fell and aggravated his hip problem.

But it's not just his body which is letting him down, Kyrgios also blamed mental problems for hampering his preparation.

"Just in general. It's not motivation, just off-court issues, I guess," he said.

That was abundantly clear on Thursday when he spent a change of ends staring at his mother in the stands saying "I don't want to play."

According to US tennis writer Ben Rothenberg - who has had his fair share of run-ins with Kyrgios on social media - the Aussie needs to take a leaf out of Roger Federer's book to rediscover his passion and drive.

"Until that mindset changes, Kyrgios shouldn’t play. Simple as that", Rothenberg wrote for Fox Sports..

"Go home, put down the racquet, and don’t pick it up until you’re sure you’re ready.

"Roger Federer did it with considerable success twice in the last 12 months, winning both the Australian Open and Wimbledon this year after a preceding rest period of several months."

Federer has flagged his intention to pick and choose which tournaments he plays for the rest of his time on tour, as we saw when he sat out the whole clay-court season this year.

After an injury-plagued second half of 2016, the Swiss great has come back bigger and better than ever, winning titles in Miami, Indian Wells and Halle to go with his two grand slam triumphs.

"It might not result in slam titles, but there would be benefits for many players by hitting the pause button," Rothenberg said.

"The hamster wheel of the tour is unceasing, and asserting a degree of autonomy in scheduling against that force can be restorative and empowering."

Aussie great Pat Cash echoed Rothenberg's sentiments when commenting about Novak Djokovic recently.

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Djokovic will miss the rest of 2017 with an elbow injury and has dropped outside the world top 4 for the first time in 10 years, but Cash sees a silver lining.

"Djokovic's style is very similar to almost everyone else on the circuit, but he was just that bit fitter, that bit more flexible, that bit more mentally tough," Cash told BBC.

"It is probably just what the doctor ordered, to take time off. After so many unbelievable years, 2017 has been poor for him."

"It won't be like Roger Federer, who was winning grand slams straight out of the blocks after he came back, but some time next year he will be playing well again.

Kyrgios faces a race against time to be fit for the US Open, starting August 27, with Australia's Davis Cup semi-final set for September.

Kyrgios is very unlikely to take a break with two massive events coming up, but it certainly wouldn't be the worst idea.

with AAP